This invention concerns a postal article such as a postcard.
One of the objects of this invention is to produce a postal article on which the sender can record an audio message, which the addressee can play back.
The postal article according to the invention is of the postcard type comprising a disk, means of driving the disk and means of regulating the rotation of the said disk, a membrane connected to a pivoting pick-up arm carrying two angularly offset styli, the first stylus being a cutting stylus, whereas the second is a playing stylus, the cutting styli being designed to engage a spirally cut groove in the surface of the disk at the bottom of which is deposited a soft material such as to harden after the cutting stylus has passed, and said postal article being characterised in that the postcard is integral with a housing containing the disk, the means of driving and regulating the rotation of the said disk, the pick-up arm and the styli.
Such an arrangement makes for a postal article that is very inexpensive and very simple to use. The sender speaks into the membrane which vibrates under the effect of his voice and transmits the oscillations to the cutting stylus which produces a groove in the soft material, this material hardening after a certain period of time such that when the pick-up stylus engages with the groove the horizontal oscillations of the said pick-up stylus are converted into vertical oscillations of the membrane to play back the recording.
According to a constructional detail, the soft material is protected by a mask consisting of an adhesive strip glued on the upper surface of the disk, one end of which passes over a slot in the housing so as to be pulled off.
According to a constructional feature, the driving means comprise a wheel the axle of which is connected to a spiral spring which, through a kinematic linkage, drives the disk axle, the said axle being connected by a kinematic linkage to a shaft carrying a mass constituting the regulator.
Preferably, means of stopping the wheel in the driving means are provided.
The postal article may comprise means for returning the playing stylus to the beginning of the groove so that the message can be played again.
According to a constructional detail, the playing arm comprises a stud moving in a curved aperture in the bottom of the housing.
The curved aperture is preferably masked by a pull-off film.
Means for rewinding the spiral spring may be provided.
According to a constructional detail, the axle of the drive wheel projects from the outer surface of the bottom of the housing and incorporates a slot for inserting a coin, the said axle being connected to unidirectional means of locking.
The end of the axle incorporating the slot is preferably masked by a tear-off film.
To enable the cutting stylus to be guided to the centre of the groove, the said groove has a V-shaped cross-section.
According to a special constructional detail, the drive wheel is connected to the axle of the disk with a reduction ratio such that one revolution of the drive wheel corresponds to approximately ten revolutions of the disk.
According to yet another constructional detail, the membrane is extended by a jacket filled with a fluid wherein a curved rod slides.
According to a constructional variant, the membrane is connected by a wire to the stylus arm, the wire being guided over a pulley.
According to yet another constructional variant, the membrane is connected by a jacket to a bellows permeable to air, the said bellows being connected to the stylus arm.
Arrangements may be made for the playing stylus to be connected by an amplifier to a loudspeaker.
Finally, according to a final characteristic, means of heating the cutting stylus may be provided in order to soften the material filling the groove during the cutting process.